Scientists say research into the genetics of inflammatory bowel disease -- which includes Crohn's disease and ulcerative colitis -- is revealing new insights into the origin of this set of illnesses. The researchers said they have linked genetic variations in 163 regions of the human genome with a heightened risk of developing inflammatory bowel disease (IBD). Of those regions, 71 are newly discovered. IBD comprises a group of chronic, autoimmune digestive disorders that affect 2.5 million people worldwide. Symptoms include abdominal pain and diarrhea and patients typically require lifelong treatment with drug therapy. Many also require surgery to repair tissue damage caused by the disease.